comment_brewfile

#!/usr/bin/env ruby
##########################################
###
##  File: comment_brewfile
##  Desc: Add comments to a Brewfile
##
#

require 'amazing_print'
require 'pathname'
require 'ruby-progressbar'

class NilClass
  def split(*args)
    [" "]
  end
  def strip
    ""
  end
  def to_s
    ""
  end
  def empty?
    true
  end
end


last_desc_start_col = 30  # Pick an acceptable starting place


if ARGV.empty?
  brewfile_path = Pathname.pwd
else
  brewfile_path = Pathname.new ARGV.first
end

brewfile = brewfile_path.directory? ? brewfile_path + 'Brewfile' : brewfile_path

unless brewfile.exist?
  puts
  puts "ERROR: Invalid path - 'Brewfile' does not exist"
  puts "       #{brewfile.parent}"
  puts
  exit(1)
end

brewfile_bak = Pathname.new (brewfile.to_s + '.bak')

brewfile.rename( brewfile_bak )

brewfile = brewfile.open('w')

brewfile_lines = brewfile_bak.read.split("\n")

progressbar = ProgressBar.create(
    title: 'Packages',
    total: brewfile_lines.size,
    format: '%t: [%B] %c/%C %j%% %e',
    output: STDERR
  )

brewfile_lines.each do |a_line|
  progressbar.increment

  if a_line.include?('#')
    # don't document something that is already documented
    # Also by side-effect ignores comment lines
    brewfile.puts a_line.chomp
    last_desc_start_col = a_line.index('#')
    next
  end

  a_line.chomp!

  if a_line.empty?
    brewfile.puts
    next
  end

  # At this point a_line should only contain a package name

  summary     = `brew info #{a_line}`.split("\n")[1] # summary is always the 2nd line

  unless summary.empty?

    sz          = a_line.length
    spacer_cnt  = last_desc_start_col - sz

    if spacer_cnt <= 0
      spacer_cnt          = 2               # number of spaces past end of current line
      last_desc_start_col = sz + spacer_cnt
    end

    a_line += (" "*spacer_cnt) + "# #{summary}"

  end # unless summary.empty?

  brewfile.puts a_line

end # of brewfile.readlines.each do |a_line|

brewfile.close